FUSE OF SEMICONDUCTOR DEVICE AND METHOD FOR FORMING THE SAME
A fuse of a semiconductor device may include: fuse link suitable for extending in a first direction and connecting first and second electrodes; a dummy strip suitable for extending in the first direction, and with a predetermined distance from the fuse link in a second direction perpendicular to the first direction; and an air channel formed between the fuse link and the dummy strip to contact with the fuse link.
The present application claims priority of Korean Patent. Application No. 10-2017-0048017, filed on Apr. 13, 2017, which is herein incorporated by reference in its entirety.
BACKGROUND 1. FieldVarious embodiments relate to a semiconductor device, and more particularly, to a fuse of a semiconductor device and a method for forming the same.
2. Description of the Related ArtIn general, a fuse of a semiconductor device may be used for implementing redundancy, tuning a circuit, storing information, or changing an electrical chip identification (ID) and structure, in order to raise the chip yield in a semiconductor device such as a Complementary Metal Oxide Semiconductor (CMOS) chip.
For example, a semiconductor memory device may use a fuse circuit to implement memory redundancy. A memory device such as DRAM includes a large number of cells, but may be determined to be a defective product even though a defect occurs in any one of the cells. When the memory device is discarded as a defective product even through a defect occurred only in a small number of cells, it is inefficient in terms of the yield. Therefore, the defective cells can be replaced with redundancy memory cells installed in the memory device through a fuse, in order to increase the yield. Furthermore, the fuse technology may be applied to not only a memory, but also a semiconductor logic circuit for tuning a circuit or changing an electrical chip ID and structure.
One of requirements for the fuse technology is to reduce a fuse area, and a selection element which occupies most of the fuse area. Therefore, there is a demand for a technique capable of lowering a program current applied to the selection element in order to reduce an area of a program transistor for providing the program current in the fuse.
SUMMARYVarious embodiments are directed to a fuse of semiconductor device, which can be blown at a low program current, and a method for forming the same.
In an embodiment, a fuse of a semiconductor device may include: a fuse link suitable for extending in a first direction and connecting first and second electrodes; a dummy strip suitable for extending in the first direction, and with a predetermined distance from the fuse link in a second direction perpendicular to the first direction; and an air channel formed between the fuse link and the dummy strip to contact with the fuse link.
In an embodiment, a fuse link suitable for extending in a first direction and connecting first and second electrodes; a dummy strip suitable for extending in the first direction, and with a predetermined distance from the fuse link in a second direction perpendicular to the first direction; and a plurality of air holes having a periodic pattern and formed between the fuse link and the dummy strip in a vertical direction of the fuse link.
In an embodiment, a method for forming a fuse of a semiconductor device may include: forming a fuse link and a dummy strip extending in a first direction in a first insulating layer, the dummy strip being adjacent to the fuse link in a second direction perpendicular to the first direction; forming an air channel between the fuse link and the dummy strip, the air channel being in contact with the fuse link and forming a second insulating layer over the fuse link, the dummy strip and the air channel without filling the air channel.
In an embodiment, a method for forming a fuse of a semiconductor device may include: forming a fuse link and a dummy strip extending in a first direction in a first insulating layer, the dummy strip being adjacent to the fuse link in a second direction perpendicular to the first direction; forming a plurality of air holes having a periodic pattern between the fuse link and the dummy strip in a vertical direction of the fuse link; and forming a second insulating layer over the fuse link, the dummy strip and the air holes, without filling the air holes.
According to the present embodiments, fuse blowing can be performed at a lower program current, and the area of the program transistor can be significantly reduced, which makes it possible to reduce the area per fuse bit while improving the reliability.
Various embodiments will be described below in detail with reference to the accompanying drawings, so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Throughout the disclosure, like reference numerals refer to like parts throughout the various figures and embodiments of the present disclosure.
Moreover, detailed descriptions related to well-known functions or configurations will be omitted in order not to unnecessarily obscure the subject matter of the present disclosure.
Terms, such as first and second, may be used to describe various components, but the components are not limited by the terms, and the terms are used to distinguish one component from another component.
Referring to
The fuse link 20 may extend in a first direction between the first and second electrodes 22 and 24 and may be formed of an electrically programmable material, so as to electrically connect the first and second electrodes 22 and 24. The fuse link 20 may be formed of a metallic material such as copper. The first electrode 22 may be referred to as a cathode, and the second electrode 24 may be referred to as an anode. The first electrode 22 may receive a negative voltage or ground voltage through a program transistor (not illustrated), and the second electrode 24 may receive a positive voltage through the program transistor. The fuse link 20 may be integrated with the first and second electrodes 22 and 24, and may be formed of the same material as the first and second electrodes 22 and 24. Fuse programming may include a process of passing a program current through the fuse link 20 by applying a voltage to the first and second electrodes 22 and 24.
When a fusing signal is applied to the gate of the program transistor, a program current flows through the fuse link 20 due to a potential difference between the first and second electrodes 22 and 24. The program current causes electro-migration and thermos-migration in the fuse link 20. Through this process, the fuse link 20 may be blown.
When a negative voltage is applied to the first electrode 22 and a positive voltage is applied to the second electrode 24, a flow of electrons from the first electrode 22 serving as the cathode to the second electrode 24 serving as the anode may occur in the fuse link 20. When electrons migrate in the fuse link 20, the electrons may collide with atoms constituting the fuse link 20, thereby causing electro-migration to migrate the atoms.
The drivability caused by the electro-migration in the fuse link 20 may be varied by changing the cross-sectional area of the fuse link 20.
When a program current flows through the fuse link 20, Joule's heat may be generated in the fuse link 20. The Joule's heat generated by the program current may have a non-uniform temperature distribution in the fuse link 20. The non-uniform temperature distribution in the fuse link 20 may exhibit the highest temperature at the central portion of the fuse link 20.
The non-uniform temperature distribution may cause thermos-migration of atoms in the fuse link 20. The thermos-migration may include thermos-migration in which atoms migrate toward the anode from the central portion of the fuse link 20 and thermos-migration in which atoms migrate toward the cathode from the central portion of the fuse link 20. The electronic drivability and thermal drivability respectively caused by the electro-migration and thermos-migration in the fuse link 20 may be added to blow the fuse link 20.
The dummy strip 30 may be disposed adjacent to the fuse link 20, and formed in parallel to the first direction in which the fuse link 20 extends. The dummy strip 30 may extend in the first direction, and with a predetermined distance from the fuse link 20 in a second direction perpendicular to the first direction. In an embodiment, the dummy strip 30 may extend in a direction which has a minute angle to the first direction, which differs from a perfect parallel. The dummy strip 30 may include a first dummy strip 31 and a second dummy strip 32, which are formed at both sides of the fuse link 20 and with a predetermined distance from the fuse link 20 in the second direction, and extend in the first direction.
The dummy strip 30 may be formed of the same material as the first and second electrodes 22 and 24 and the fuse link 20. For example, the dummy strip 30 may be formed of a metallic material such as copper.
The air channel 40 may be formed between the fuse link 20 and the dummy strip 30. The air channel 40 may be formed in contact with a side surface of the fuse link 20. The air channel 40 may be formed to contact both sides of the fuse link 20 and one side of the dummy strip 30. The air channel 40 may have a lower dielectric constant than the insulating layer 10. The insulating layer 10 may be formed of a low-k dielectric. The low-k dielectric may include a material having a lower dielectric constant than silicon oxide (SiO2) used as a semiconductor interlayer dielectric material.
The air channel 40 may serve as a thermal insulator and crack stopper during fuse program. Since the fuse link 20 is insulated from Joule's heat by the air channel 40 during fuse program, the thermal drivability caused by thermos-migration and the electronic drivability caused by electro-migration can be improved. Therefore, the air channel 40 can allow the fuse to be blown at a lower program current, and prevent a damage of the surrounding structure during fuse blowing. As a result, since the area of the program transistor is significantly reduced, the area per fuse bit can be reduced while the reliability is improved.
The insulating layer 10 may cover the first and second electrodes 22 and 24, the fuse link 20, the dummy strip 30 and the air channel 40. The insulating layer 10 may be formed of a low-k dielectric having a lower dielectric constant than silicon oxide (SiO2) which is used as a semiconductor interlayer dielectric material.
Referring to
Since the air channel 40 insulates the fuse link 20 from Joule's heat generated therein during fuse program, the air channel 40 can improve the thermal drivability caused by thermos-migration and the electronic drivability caused by electro-migration. The air channel 40 may prevent a damage of the surrounding structures during fuse program. According to the present embodiment, fuse blowing can be performed at a low program current, and the fuse link 20 can be stably blown. Therefore, the area of the program transistor can be significantly reduced, which makes it possible to decrease the area per fuse bit while improving the reliability.
Referring to
The fuse link 20 may extend in a first direction between the first and second electrodes 22 and 24 and may be formed of an electrically programmable material, so as to electrically connect the first and second electrodes 22 and 24. The fuse link 20 may be formed of a metallic material such as copper. The first and second electrodes 22 and 24 and the fuse link 20 may be integrated with each other, and formed of the same material.
During fuse program, a program current flows through the fuse link 20, and causes electro-migration and thermos-migration in the fuse link 20. Through this process, the fuse link 20 may be blown.
The dummy strip 30 may be disposed adjacent to the fuse link 20, and be formed in parallel to the first direction in which the fuse link 20 extends. The dummy strip 30 may extend in the first direction, and with a predetermined distance from the fuse link 20 in a second direction perpendicular to the first direction. The dummy strip 30 may include a first dummy strip 31 and a second dummy strip 32, which are formed at both sides of the fuse link 20 and with a predetermined distance from the fuse link 20 in the second direction, and extend in the first direction. The dummy strip 30 may be formed of the same material as the first and second electrodes 22 and 24 and the fuse link 20. For example, the dummy strip 30 may be formed of a metallic material such as copper.
The air holes 50 may be formed between the fuse link 20 and the dummy strip 30. The air holes 50 may be formed in a vertical direction of the fuse link 20 between the fuse link 20 and the dummy strip 30 in the insulating layer 10. The air holes 50 may be arranged between the fuse link 20 and the dummy strip 30, while having a periodic pattern. Each of the air holes 50 may be formed with a nano-sized hole. The air holes 50 may have a lower dielectric constant than the insulating layer 10. The insulating layer 10 may be formed of a low-k dielectric. The low-k dielectric may include a material having a lower dielectric constant than silicon oxide (SiO2) which is used as a semiconductor interlayer dielectric material.
The air holes 50 may serve as a thermal insulator and crack stopper during fuse program. Since the fuse link 20 is insulated from Joule's heat generated therein by the air holes 50 during fuse program, the thermal drivability caused by thermos-migration and the electronic drivability caused by electro-migration can be improved. Therefore, the air holes 50 may allow the fuse to be blown at a lower program current. Also, the air holes 50 may prevent a damage of the surrounding structures during fuse blowing. According to the present embodiment, the area of the program transistor can be significantly reduced to decrease the area per fuse bit, and the fuse link 20 can be stably blown.
Referring to
Since the air holes 50 insulate the fuse link 20 from the Joule's heat generated therein during fuse program, the air holes 50 can improve the thermal drivability caused by thermos-migration and the electronic drivability caused by electro-migration. Furthermore, the air holes 50 may prevent a damage of the surrounding structures during fuse program According to the present embodiment, fuse blowing can be performed at a low program current, and the fuse link 20 can be stably blown. Therefore, the area of the program transistor can be significantly reduced, which makes it possible to decrease the area per fuse bit while improving the reliability.
Referring to
The first insulating layer 10A may have a thickness enough to form the fuse link 20 and the dummy strip 30. The first insulating layer 10A may be partially etched to form the fuse link 20 and the dummy strip 30.
The fuse link 20 may extend between the first and second electrodes 22 and 24 (refer to
Referring to
The air channel 40 may be formed by the following process.
First, the position of the air channel 40 which is to be formed in the first insulating layer 10A may be defined through a photo-resist coating process, an exposure process and a develop process. For this operation, the top surfaces of the fuse link 20 and the dummy strip 30 and the top surface of the first insulating layer 10A may be coated with photo resist 12. The photo resist 12 may include photosensitive resin which is applied to the first insulating layer 10A in order to form the air channel 40 in a lithography process which is one of several semiconductor processes.
A part of the first insulating layer 10A may be etched. At this time, the part, of the first insulating layer 10A may correspond to the position defined by the photo resist 12. Then, the part of the first insulating layer 10A may be etched to form the air channel 40 at the same level or height as the fuse link 20 in a vertical direction of the fuse link 20.
Referring to
Referring to
First, referring to
The fuse link 20 may extend between the first and second electrodes 22 and 24 (refer to
In order to form air holes 50, a hard mask 14 may be formed over the fuse link 20, the dummy strip 30 and the insulating layer.
Then, referring to
Referring to
In order to form the air holes 50 having a periodic pattern in the self-assembly polymer 16 and the hard mask 14, the self-assembly polymer 16 and the hard mask 14 may be partially etched. The self-assembly polymer 16 may include a material obtained by synthesizing polystyrene and methyl-methacrylate. For example, the polystyrene of the self-assembly polymer 16 may be rearranged to form a periodic pattern after annealing. The polystyrene of the self-assembly polymer 16 may be selectively removed by wet or dry etching, and form the air holes 50 with a periodic pattern.
Referring to
Referring to
Referring to
Referring to
According to the present embodiments, fuse blowing can be performed at a lower program current, and the area of the program transistor can be significantly reduced, which makes it possible to reduce the area per fuse bit while improving the reliability.
Although various embodiments have been described for illustrative purposes, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
Claims
1. A fuse of a semiconductor device, comprising:
- a fuse link suitable for extending in a first direction and connecting first and second electrodes;
- a dummy strip suitable for extending in the first direction, and with a predetermined distance from the fuse link in a second direction perpendicular to the first direction; and
- an air channel formed between the fuse link and the dummy strip to contact with the fuse link.
2. The fuse of claim 1, wherein the fuse link, the dummy strip and the air channel are formed in an insulating layer, and the air channel has a lower dielectric constant than the insulating layer.
3. The fuse of claim 1, wherein the air channel is formed to contact both sides of the fuse link.
4. The fuse of claim 3, wherein the air channel is formed to contact both sides of the fuse link and one side of the dummy strip.
5. The fuse of claim 1, wherein the air channel is formed at the same level as the fuse link in a vertical direction of the fuse link.
6. The fuse of claim 1, wherein the air channel is formed at the same level as the fuse link and the dummy strip in a vertical direction of the fuse link.
7. The fuse of claim 1, wherein the dummy strip includes first and second dummy strips which are formed at both sides of the fuse link at the predetermined distance from the fuse link in the second direction, and extend in the first direction, and
- the air channel is formed between the fuse link and each of the first and second dummy strips to contact both sides of the fuse link and one side of each of the first and second dummy strips.
8. A fuse of a semiconductor device, comprising:
- a fuse link suitable for extending in a first direction and connecting first and second electrodes;
- a dummy strip suitable for extending in the first direction, and with a predetermined distance from the fuse link in a second direction perpendicular to the first direction; and
- a plurality of air holes having a periodic pattern and formed between the fuse link and the dummy strip in a vertical direction of the fuse link.
9. The fuse of claim 8, wherein the fuse link, the dummy strip and the air holes are formed in an insulating layer, and the air holes have a lower dielectric constant than the insulating layer.
10. The fuse of claim 8, wherein the air holes are formed at the same level as the fuse link in the vertical direction of the fuse link.
11. The fuse of claim 8, wherein the air holes are formed at the same level as the fuse link and the dummy strip in the vertical direction of the fuse link.
12. The fuse of claim 8, wherein the air holes have a nano-size.
13. The fuse of claim 8, wherein the dummy strip includes first and second dummy strips which are formed at both sides of the fuse link at the predetermined distance from the fuse link in the second direction and extend in the first direction, and
- the air holes are arranged between the fuse link and each of the first and second dummy strips while having the periodic pattern, and formed in the vertical direction of the fuse link.
14. A method for forming a fuse of a semiconductor device, comprising:
- forming a fuse link and a dummy strip extending in a first direction in a first insulating layer, the dummy strip being adjacent to the fuse link in a second direction perpendicular to the first direction;
- forming an air channel between the fuse link and the dummy strip, the air channel being in contact with the fuse link; and
- forming a second insulating layer over the fuse link, the dummy strip and the air channel without filling the air channel.
15. The method of claim 14, wherein the forming of the air channel comprises:
- coating a photo resist on the top surfaces of the fuse link, the dummy strip and the first insulating layer;
- exposing and developing the photo resist between the fuse link and the dummy strip, and etching a part of the first insulating layer such that the air channel is formed at the same level as the fuse link in a vertical direction of the fuse link while being in contact with both sides of the fuse link and one side of the dummy strip; and
- removing the photo resist.
16. The method of claim 15, wherein the first and second insulating layers are formed of a low-k dielectric and the air channel has a lower dielectric constant than the first and second insulating layers.
17. A method for forming a fuse of a semiconductor device, comprising:
- forming a fuse link and a dummy strip extending in a first direction in a first insulating layer the dummy strip being adjacent to the fuse link in a second direction perpendicular to the first direction;
- forming a plurality of air holes having a periodic pattern between the fuse fink and the dummy strip in a vertical direction of the fuse link; and
- forming a second insulating layer over the fuse link, the dummy strip and the air holes without filling the air holes.
18. The method of claim 17, wherein the forming of the air holes comprises:
- forming a hard mask over the fuse link, the dummy strip and the insulating layer;
- coating a top surface of the hard mask with a photo resist;
- exposing and developing a part of the photo resist between the fuse link and the dummy strip;
- forming self-assembly polymer over the photo resist and the hard mask;
- annealing the self-assembly polymer such that the air holes having the periodic pattern are formed in the self-assembly polymer;
- etching the hard mask to form the air holes in the hard mask;
- removing the photo resist and the self-assembly polymer;
- etching the first insulating layer such that the air holes formed in the hard mask are transferred into the first insulating layer; and
- removing the hard mask.
19. The method of claim 18, wherein the first insulating layer is etched to form the air holes at the same level as the fuse link and the dummy strip in the vertical direction of the fuse link.
20. The method of claim 18, wherein the first and second insulating layers are formed of a low-k dielectric, and the air holes have a lower dielectric constant than the first and second insulating layers.
Type: Application
Filed: Oct 20, 2017
Publication Date: Oct 18, 2018
Patent Grant number: 10607934
Inventors: Deok-Kee KIM (Seoul), Jae Hong KIM (Gyeonggi-do), Seo Woo NAM (Gyeonggi-do)
Application Number: 15/788,922